Add Holger Weiss to hall of fame

Permission obtained from Holger Weiss to include all of his contributions to Git into LibGit2. See https://github.com/git/git/commit/21e403a7b956a95a36f218439f82b1c8af869257
Add Dmitry Kakurin to hall of fame

See lines 59-60 from https://github.com/libgit2/libgit2/blob/44b1ff4c1209c34360cc0c43761c40f5f5020886/src/filter.c which contain a couple of lines of code to ignore an EOF at the end of a file when detecting if it is a text file or not. These came from this contribution that Dmitry made to core Git back in 2008 (https://github.com/git/git/commit/f9dd4bf4e58af0b4828c7e7013080dba59f8a6b9) which was committed by Junio.

Dmitry gave his permission for these changes to be included in LibGit2 as well via email to vmg and myself
Add new email address for Nicolas Pitre

See https://github.com/git/git/commit/03aa8ff3be3b35522b2e378651e65e0e86778018, Nicolas Pitre's email address has changed to nico@fluxnic.net
Minor optimization to tree entry validity check

This checks for a leading '.' before looking for the invalid
tree entry names.  Even on pretty high levels of optimization,
this seems to make a measurable improvement.

I accidentally used && in the check initially instead of || and
while debugging ended up improving the error reporting of issues
with adding tree entries.  I thought I'd leave those changes, too.
Fix win32 lstat
Set up default internal ignores

This adds "." ".." and ".git" to the internal ignores list by
default - asking about paths with these files will always say
that they are ignored.
Improve iterator ignoring .git file

The workdir iterator has always tried to ignore .git files, but
it turns out there were some bugs.  This makes it more robust at
ignoring .git files.

This also makes iterators always check ".git" case insensitively
regardless of the properties of the system.  This will make libgit2
skip ".GIT" and the like.  This is different from core git, but on
systems with case insensitive but case preserving file systems,
allowing ".GIT" to be added is problematic.
update win32 lstat comment
Update clar tests p_lstat_posixly and p_lstat
Minor optimization in win32 do_lstat
It is okay to not have a .gitconfig file

Opening a repo is generating an error if you don't have a
.gitconfig file in your home directory, but that should be
legal.
Merge pull request #1089 from edubart/fix_win32_lstat

Fix win32 lstat
Merge branch 'development' of https://github.com/libgit2/libgit2 into development
Need to clear ignored error from config load
Merge pull request #1092 from arrbee/legal-to-not-have-gitconfig

It is okay to not have a .gitconfig file
Add contributing guidelines
Markdownize CONVENTIONS
Rewrite conventions to be more complete
Merge branch 'development' of https://github.com/libgit2/libgit2 into development
Merge pull request #1095 from martinwoodward/authors

Update to Authors